The purpose of this research study is to develop a method to prevent diabetes through a nationwide study designed to identify individuals who are at risk of developing Type 1 Insulin Dependent Diabetes Mellitus (IDDM), the form of diabetes most common in children and young adults, and then to attempt to prevent the development of diabetes in subjects at high risk. This study is designed to characterize the immune system and pancreas function in individuals who are at risk who are at risk of developing IDDM.